1. Field of Invention
The present invention relates to an efficient gas-powered glue gun.
2. Background of Invention
According to U.S. Pat. No. 5,799,648, a conventional glue gun 80 includes a shell 81 including a main portion 82 and a handle portion 83. A main body 85 is installed in the main portion 82 of the shell 81. The main body 85 defines a combustion chamber 10 and an exhaust port 21 in communication with the combustion chamber 10. A combustion element 12 is disposed in the combustion chamber 10. A barrel 84 is disposed in the main portion 82 of the shell 81. The barrel 84 is connected with the main body 85 so that heat can be transferred to the barrel 84 from the main body 85. Solid glue is fed into the barrel 84. The solid glue is heated and molten in the barrel 84. The molten glue is dispensed from the barrel 84. Problems have been encountered in the use of the glue gun 80. Firstly, it takes quite some time for heat to reach the barrel 84 from the main body 85. This entails a high operative cost. Secondly, it is difficult for hot exhaust to leave the combustion chamber 10 through the exhaust port 21 because the hot exhaust tends to rise while the exhaust port 21 extends downwards. An undesired amount of heat accumulates in the combustion chamber 10. The temperature of the main body 85 and the barrel 84 reaches an undesired value. This high temperature may damage the glue gun and hurt a user.
As disclosed in U.S. Pat. Nos. 5,901,881 and 5,960,996, a combustion chamber is located in a lower portion of a barrel. Therefore, it is hard to expel hot exhaust.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in the prior art.